propionat

Propionat, or propionate, refers to the conjugate base or salts of propionic acid (propanoic acid). The propanoate ion has the formula CH3CH2COO−. In neutralized form, common salts include sodium propionate, potassium propionate and calcium propionate. Propionic acid is a colorless, oily liquid with a sharp odor; the salts are usually solids and are more stable.

Propionates occur naturally as a product of fermentation; a significant amount of propionate is produced by gut microbiota from dietary fiber and may enter systemic circulation, where it can be used as a substrate for gluconeogenesis or act as a signaling molecule.

Industrial production typically involves neutralization of propionic acid with bases to form salts, which are widely used as food preservatives because they inhibit mold and some bacteria. Sodium propionate and calcium propionate are common preservatives in baked goods, dairy products, and processed meats; they are also used as feed additives.

Propionates also serve as intermediates in organic synthesis and as esterifying groups in pharmaceutical propionate esters. In medicine, propionate esters of corticosteroids (e.g., fluocinolone propionate, methylprednisolone propionate) exploit lipophilicity for topical delivery.

Safety and regulation: Propionic acid and its salts are generally recognized as safe in approved uses; handling of propionic acid requires care due to irritation of skin and eyes. As with any food additive or chemical, regulatory status depends on jurisdiction and application.

See also: Propionic acid; Propanoate; List of food additives.